The intrinsic muscles of the syrinx fixed to the ends of the bronchial semi-rings; the edges of the mandibles smooth; the hinder part of the tarsus longitudinally bilaminated, the laminae entire and smooth; wing with nine primaries, the first and second about equal in length ; secondary quills reaching about three-quarters the length of the wing; bill more or less conical; tail of twelve feathers; tarsus scutellated; nostrils pierced close to the line of the forehead and very near the culmen; rictal bristles few and short; plumage of nestling various; . sexes generally dissimilar.
The Fringillidae or Finches comprise a very large number of birds which have a considerable general resemblance to each other, and are characterized by points of structure which render their separation from other groups comparatively easy.
Although Finches have, as a rule, but one moult a year, yet their summer and winter plumages differ considerably in many of the species. In spring and summer the margins of the feathers are lost by abrasion or by being cast off, and then the colour of the parts affected becomes more uniform and frequently more brilliant.
The Finches are normally granivorous or frugivorous, but they also eat insects and the young are fed entirely on these. They are for the most part gregarious and arboreal, but they descend to the ground freely to pick up food. Many of them are good songsters, and they are all hardy and bear captivity well.
Sharpe, in the twelfth volume of the British Museum Catalogue of Birds, has treated this family in a very complete and satisfactory manner. This was the first Catalogue written by him with the combined Hume and Tweeddale Collections at his disposal. I follow him in the arrangement of this group, and I have found no reason to differ from him except in some minor matters, such as the extent of a few of the genera.
The Fringillidae may be divided into three very natural subfamilies by the character of the shape of the skull and bill.
Upper mandible produced backwards beyond the front line of the bony orbit; inferior outline of lower mandible straight or nearly so……………………Coccothraustinae., p. 196.
Upper mandible not produced backwards beyond front line of orbit; inferior outline of lower mandible with a slight re-entering angle ; cutting-edges of upper and lower mandibles everywhere in contact……………………Fringillinae, p. 202.
Upper mandible not produced backwards beyond front line of orbit; inferior line of lower mandible greatly angulate; cutting-edges of mandibles not everywhere in contact, but leaving a gap of greater or less extent……………………Emberizinae, p. 249.